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Öğe Donor-acceptor heterojunction solar cells based on perylene dimide and perylene bisbenzimidazole(Cambridge Univ Press, 2006) Erten, S.; Meghdadi, F.; Gunes, S.; Koeppe, R.; Sariciftci, N. S.; Icli, S.We have fabricated heterojunction solar cells comprising active layers of perylene diimide (PDI) or perylene bisbenzimidazole (CONPER, conjugated perylene dye) as electron acceptor and ZnPC as donor. Bilayer solar cells were produced by successive evaporation of zinc phthalocyanine (ZnPC) and perylene diimide (PDI) or perylene bisbenzimidazole (CONPER) on glass substrates coated with indium doped tin oxide. Active layers with different thickness were evaporated. The bilayer cells were characterized under simulated AM 1.5 illumination (100 mW/cm(2)). The best results were obtained for the device structure of ITO/PEDOT/ZnPC (40 nm)/perylene bisbenzimidazole (60 nm)/Al (70 nm).Öğe Dye sensitized solar cell based on 1,8-naphthalene benzimidazole comprising carboxyl group(Edp Sciences S A, 2007) Erten, S.; Eren, E.; Icli, S.We report the characterization of 1,8-naphtha naphthalene benzimidazole comprising carboxyl group.We have fabricated dye-sensitized nanocrystalline TiO2 solar cell (DSSC) based on naphthalene benzimidazole dye. The device structure is FTO/nc-TiO2/Dye/I-/I-3(-)/Pt/ FTO. We calculated the E-HOMO and E-LUMO levels of this new dye by using cyclic voltammetry measurement. The E-LUMO level of naphthalene benzimidazole is 3.2 eV. This value is higher than the conduction band of TiO2. Electrons can be injected to the conduction band of TiO2. The current-voltage (I-V) characteristic of cell was measured under simulated AM 1.5 illumination (100 mW/cm(2)). We obtained the open circuit voltage; V-oc = 0.344 V, short circuit current density; I-sc = 5.93 mA cm(-2), filling factor; FF = 0.45, power conversion efficiency; eta = 0.91%.Öğe Impedance ratio: a novel marker and a powerful predictor of mortality in hemodialysis patients(Springer, 2016) Demirci, C.; Asci, G.; Demirci, M. S.; Ozkahya, M.; Toz, H.; Duman, S.; Sipahi, S.; Erten, S.; Tanrisev, M.; Ok, E.Impedance ratio (Imp-R) obtained by multifrequency bioimpedance analysis (BIA) has been shown to be associated with volume and nutrition status. In this prospective study, the predictive role of Imp-R for mortality in hemodialysis (HD) patients was investigated. Multifrequency (5-50-100-200 kHz) BIA was applied to 493 prevalent HD patients in March-April 2006. Imp-R was defined as the ratio of 200-5 kHz impedance values. Demographical, clinical and laboratory data at the time of the analysis were recorded. All-cause and cardiovascular (CV) mortality were assessed during 3 years of follow-up. Mean age was 57.7 +/- 13.9 years, HD duration 52.1 +/- 42.6 months and prevalence of diabetes 21.7 %. Imp-R was negatively correlated with nutritional markers including albumin, creatinine and hemoglobin levels. In addition, there was a positive correlation between Imp-R and age, ratio of extracellular water to total body water and high-sensitive C-reactive protein. Over a mean follow-up period of 27.9 +/- 11.1 months, 93 deaths (52 from CV reasons) were observed. In the multivariate analysis, Imp-R was significantly associated with all-cause and CV mortality after adjustments [HR 1.13, 95 % CI (1.04-1.23); p = 0.004 and HR 1.15, 95 % CI (1.03-1.27); p = 0.01, respectively]. The risk of all-cause mortality was 3.4 times higher in the fourth quartile of Imp-R (> 83.5 %) compared to the first Imp-R quartile (< 78.8 %) as reference. Cutoff value of Imp-R for all-cause mortality was 82.0 % with a sensitivity of 65.5 % and specificity of 64 %. Impedance ratio measured by multifrequency in standardized conditions BIA is an independent and powerful predictor of both all-cause and CV mortality in hemodialysis patients.Öğe Patient Survival With Extended Home Hemodialysis Compared to In-center Conventional Hemodialysis(Elsevier Inc., 2023) Ok, E.; Demirci, C.; Asci, G.; Yuksel, K.; Kircelli, F.; Koc, S.K.; Erten, S.Introduction: More frequent and/or longer hemodialysis (HD) has been associated with improvements in numerous clinical outcomes in patients on dialysis. Home HD (HHD), which allows more frequent and/or longer dialysis with lower cost and flexibility in treatment planning, is not widely used worldwide. Although, retrospective studies have indicated better survival with HHD, this issue remains controversial. In this multicenter study, we compared thrice-weekly extended HHD with in-center conventional HD (ICHD) in a large patient population with a long-term follow-up. Methods: We matched 349 patients starting HHD between 2010 and 2014 with 1047 concurrent patients on ICHD by using propensity scores. Patients were followed-up with from their respective baseline until September 30, 2018. The primary outcome was overall survival. Secondary outcomes were technique survival; hospitalization; and changes in clinical, laboratory, and medication parameters. Results: The mean duration of dialysis session was 418 ± 54 minutes in HHD and 242 ± 10 minutes in patients on ICHD. All-cause mortality rate was 3.76 and 6.27 per 100 patient-years in the HHD and the ICHD groups, respectively. In the intention-to-treat analysis, HHD was associated with a 40% lower risk for all-cause mortality than ICHD (hazard ratio [HR] = 0.60; 95% confidence interval [CI] 0.45 to 0.80; P < 0.001). In HHD, the 5-year technical survival was 86.5%. HHD treatment provided better phosphate and blood pressure (BP) control, improvements in nutrition and inflammation, and reduction in hospitalization days and medication requirement. Conclusion: These results indicate that extended HHD is associated with higher survival and better outcomes compared to ICHD. © 2023Öğe Soluble derivatives of perylene and naphthalene diimide for n-channel organic field-effect transistors(Elsevier Science Bv, 2006) Singh, Th. B.; Erten, S.; Guenes, S.; Zafer, C.; Turkmen, G.; Kuban, B.; Teoman, Y.; Sariciftci, N. S.; Icli, S.Solution-processed n-type organic field-effect transistors (OFETs) have been fabricated using soluble derivatives of perylene diimide and naphthalene diimide. We report the synthesis of the organic semiconductors and the fabrication of bottom gate OFET devices using solution-processed organic dielectrics. Surface morphology studies reveal films with layered textures and liquid crystalline-like structure. Devices show field-effect electron mobilities of 10(-2) cm(2)/V s and 10(-3) cm(2)/V s for N,N'-bis-n-butyl-1,4,5,8-naphthalenediimide-NDI under inert conditions and in air, respectively. N,N'-bis-(1-pentyl)hexyl-3,4,9,10-perylene diimide-PDI-4 shows mobility of 5 x 10(-4) cm(2)/V s. Organic field-effect transistors based on N,N'-bis(dehydroabietyl)-3,4,9,10-perylene diimide-PDI-1 derivative exhibit ambipolar transport. (c) 2006 Elsevier B.V. All rights reserved.
